JPH06332472A - Active type noise control device and active type vibration control device - Google Patents

Abstract

PURPOSE:To enable noise reduction effect and vibration reduction effect to be obtained in wide frequency band, even if controllable frequency of a controlled sound source and a controlled vibration source is narrow. CONSTITUTION:A crank angle signal X outputted from a crank angle sensor 5 is taken in control device 10 as a signal indicating an occurrence state of vibration of an engine 4, while a residual noise signal ep1 being output of microphones 8a-8c is taken in the control device 10 as a residual noise in a vehicle compartment 3, the reference signal is generated from the crank angle signal X, and a driving signal ypm of loudspeaker 9a, 9b is generated based on the reference signal and the residual noise signal ep1. And, a rotation speed of the engine is obtained from the crank angle signal X, the order component of the crank angle signal X corresponding to the reference signal is switched so that frequency of the reference signal is kept within frequency band in which loudspeakers 9a, 9b are normally operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active noise control device for reducing noise by interfering control noise with noise transmitted from a noise source such as a vehicle engine to a space such as a vehicle compartment, a vehicle engine and the like. The present invention relates to an active vibration control device that reduces the vibration by interfering the control vibration with the vibration that is emitted from the vibration source and propagates through the vehicle body, and in particular, even if the controllable frequency band of the control sound source or the control vibration source is narrow. The noise reduction effect and the vibration reduction effect can be expected in a wide frequency band.

[0002]

2. Description of the Related Art As a conventional technique of this type, there are those described in British Patent No. 2149614 and Japanese Patent Publication No. 1-501344. These conventional devices are active noise reduction devices applied to aircraft cabins and similar closed spaces, in which a single noise source such as an engine located outside the closed space has a fundamental frequency f ₀ and It operates under the condition that noise including the harmonics f _{1 to} f _n is generated.

[0003] More specifically, includes a microphone for detecting a plurality of the installed sound pressure to a location within the closed space, and a plurality of loudspeakers for generating a control sound to the closed space, the frequency f ₀ of the noise source - Based on the f _n component, those frequencies f ₀ ~
The loudspeaker is driven by a signal having a phase opposite to that of the f _n component,
Therefore, a control sound having a phase opposite to that of the noise transmitted to the closed space is generated from the loudspeaker to cancel the noise.

Then, as a method of generating the control sound emitted from the loudspeaker, PROCEEDINGS OF THE IEEE, VOL.
63 PAGE 1692,1975, “ADAPTIVE NOISE CANSELLATION:
PRINCIPLES AND APPLICATIONS ”
An algorithm that applies the DROW LMS 'algorithm to multiple channels is applied. The content of the paper is "A MULTIPLE ERROR LMS ALGORITHM AND
ITS APPLICATION TOTHE ACTIVE CONTROL OF SOUND AND
VIBRATION ”, IEEE TRANS.ACOUST., SPEECH, SIGNAL PRO
CESSING, VOL.ASSP −35, PP. 1423−1434, 1987.

That is, the LMS algorithm is one of the algorithms suitable for updating the filter coefficient of the adaptive digital filter, and is, for example, a so-called Filter.
In the ed-X LMS algorithm, a transfer function filter that models the transfer function from the loudspeaker to the microphone is set for all combinations of the loudspeaker and the microphone, and a reference signal representing the noise generation state of the noise source is set. Update the filter coefficient of the adaptive digital filter with variable filter coefficient provided for each loudspeaker so that the value of the predetermined evaluation function based on the value processed by the filter and the residual noise detected by each microphone is reduced. is doing.

[0006]

Although it is possible to generate a drive signal capable of reducing noise according to the above-mentioned conventional technique, the frequency response of a normal loudspeaker is several tens Hz or more. Therefore, even if a driving signal having a frequency lower than that is supplied to the loudspeaker, a distorted sound is generated, which adversely deteriorates the noise level. Therefore, a loudspeaker equipped with a large-diameter and large-volume enclosure capable of sufficiently emitting such low-frequency control sound is used, or noise in a frequency band of an uncontrollable frequency band is generated. In the situation, it is necessary to stop the noise reduction control, but in the former case, not only will the cost be drastically increased, but the device will also become large, so if the space is small, such as in the passenger compartment of a vehicle, it will not be installed. This is often possible, and in the latter case, no noise reduction effect can be expected when low frequency noise occurs.

On the other hand, for example, in a so-called active engine mount, the vibration generated by the engine and transmitted to the vehicle body is reduced by appropriately driving the engine mount incorporating the electromagnetic actuator according to the above-mentioned LMS algorithm or the like. Since the frequency response of the electromagnetic actuator is as low as around 200 Hz or less, for example, the muffled sound that becomes a problem in a vehicle equipped with a 4-cylinder reciprocating engine is caused by the secondary component of the engine rotation. Therefore, the secondary component of the engine rotation is used as a reference signal. As always controlled,
There is a problem that the electromagnetic actuator does not operate accurately when the engine rotates at high speed, and eventually vibration reduction control cannot be performed when high frequency vibration occurs.

The present invention has been made by paying attention to the unsolved problems of the prior art as described above, and it is possible to control a control sound source or a controlled vibration source without causing a problem such as an increase in size of the device. It is an object of the present invention to provide an active noise control device and an active vibration control device that can expect a noise reduction effect and a vibration reduction effect even if the possible frequency band is narrow.

[0009]

In order to achieve the above object, the invention according to claim 1 is a control sound source capable of generating a control sound in a space where periodic noise is transmitted from a noise source, and the noise. Reference signal generating means for generating a reference signal consisting of a periodic signal corresponding to a predetermined order component of the periodic noise based on the noise generation state of the source, and residual noise detected at a predetermined position in the space. Residual noise detecting means for outputting as a signal, adaptive digital filter of variable filter coefficient, drive signal generating means for generating a signal for driving the control sound source by filtering the reference signal with the adaptive digital filter, and the reference Adaptive processing means for updating the filter coefficient of the adaptive digital filter so as to reduce noise in the space based on the signal and the residual noise signal. In the active noise control device, the frequency detecting means for detecting the frequency of the noise, and the order of the predetermined order component of the periodic noise corresponding to the reference signal is set to the frequency of the noise detected by the frequency detecting means. And an order switching means for switching according to the order.

According to a second aspect of the present invention, in the above-described first aspect of the invention, the order switching means sets a frequency band for generating a reference signal corresponding to one order and a reference signal corresponding to another order. It was decided to overlap the generated frequency band. According to the invention of claim 3, in the invention of claim 1, an adaptive digital filter is individually provided for each reference signal corresponding to each order component switched by the order switching means.

On the other hand, in order to achieve the above object, the invention according to claim 4 is a control vibration source capable of generating a control vibration that interferes with a periodic vibration generated from the vibration source, and a vibration of the vibration source. Reference signal generating means for generating a reference signal composed of a periodic signal corresponding to a predetermined order component of the periodic vibration based on the generation state, and residual vibration detection for detecting the vibration after the interference and outputting it as a residual vibration signal. Means, an adaptive digital filter having a variable filter coefficient, and drive signal generating means for generating a signal for driving the control vibration source by filtering the reference signal with the adaptive digital filter.
An active vibration control device comprising: an adaptive processing unit that updates a filter coefficient of the adaptive digital filter so as to reduce vibration after the interference based on the reference signal and the residual vibration signal. Frequency detection means for detecting the frequency of the periodic vibration, and order switching means for switching the order of the predetermined order component of the periodic vibration corresponding to the reference signal according to the frequency of the vibration detected by the frequency detection means. Is characterized by.

According to a fifth aspect of the present invention, in the above-mentioned fourth aspect, the order switching means sets a frequency band for generating a reference signal corresponding to one order and a reference signal corresponding to another order. It was decided to overlap the generated frequency band. In the invention according to claim 6, in the invention according to claim 4, an adaptive digital filter is individually provided for each reference signal corresponding to each order component switched by the order switching means.

[0013]

According to the present invention, the reference signal generating means generates the reference signal which is a periodic signal based on the noise generation state of the noise source, and the drive signal generating means causes the reference signal to be generated. Since a drive signal for driving the control sound source is generated by performing a filtering process on the signal with an adaptive digital filter, the drive signal becomes a periodic signal corresponding to the fundamental frequency of the noise emitted from the noise source or its harmonic component. Therefore,
When the order switching means changes the order of the order component of the periodic noise corresponding to the reference signal, the frequency of the drive signal changes.

The control sound source is driven according to the drive signal thus generated. If the frequency of the drive signal is within the frequency band in which the control sound source can normally operate, the control sound source outputs An accurate control sound is emitted according to the drive signal. However, if the frequency of the drive signal is out of the frequency band in which the control sound source can operate normally, the control sound source cannot generate a control sound that can reduce noise with the drive signal as it is, but the frequency detection means detects it. When the order switching means changes the order of the order component of the periodic noise corresponding to the reference signal according to the frequency of the generated noise, the frequency of the drive signal changes (specifically, if the order is increased, the driving is performed. Since the frequency of the signal becomes high, and conversely, if the order is made smaller, the frequency of the drive signal becomes lower), the frequency of the drive signal can be operated normally by the control sound source if the switching direction is properly selected. It comes to fit within the frequency band.

When the order of the order component of the periodic noise corresponding to the reference signal suddenly switches at a certain frequency, the update process of the filter coefficient of the adaptive digital filter cannot catch up with the change of the order, and the filter coefficient There is a possibility that the accuracy of the drive signal will be reduced until the updating process of 1 is executed a certain number of times, and the noise reduction effect cannot be obtained. Therefore, according to the invention of claim 2, when switching from one order to another order, first, a reference signal corresponding to the other order is generated, that is, the one order and the other order are generated. After the reference signals corresponding to both orders are generated, the generation of the reference signal corresponding to one order is stopped, so that the filter coefficients of the adaptive digital filter are related to the other orders. After being updated according to the signal, the switching by the order switching means is completed.

According to the third aspect of the invention, since there is an adaptive digital filter for each reference signal corresponding to the predetermined order component, a reference signal corresponding to one order,
The reference signals corresponding to other orders will be filtered by different adaptive digital filters, and the filter coefficients of the respective adaptive digital filters will be updated based on the different reference signals.

Here, while the inventions according to claims 1 to 3 are all directed to noise, claim 4
The invention according to claim 6 is intended for vibration. Therefore, the operation of the invention according to claims 4 to 6 is as follows.
Although there is a difference between sound and vibration, it is substantially the same as the invention described in claims 1 to 3 above.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are diagrams showing a configuration of a first embodiment of the present invention. In this embodiment, an active noise control device according to the present invention is used to reduce noise in a vehicle interior 3 of a vehicle 2. This is applied to an active noise control system 1 for a vehicle.

First, the structure will be described. As shown in FIG. 1, the vehicle active noise control device 1 is a muffled noise transmitted from an engine 4 as a noise source into a vehicle interior 3 as a space. In the device for reducing noise, a crank angle sensor 5 that outputs a crank angle signal X synchronized with the rotation of a crank shaft of the engine 4 is attached to the engine 4, and the crank angle sensor 5 outputs the crank angle signal. The crank angle signal X is supplied to the controller 10. In the present embodiment, a 4-cylinder reciprocating engine is assumed as the engine 4.

On the other hand, in the passenger compartment 3, a plurality of microphones 8a, 8b and 8c as residual noise detecting means for measuring the sound pressure of the noise remaining in the passenger compartment 3, and a control sound in the passenger compartment 3 are provided. A plurality of loudspeakers 9 as generated control sound sources
a and 9b are provided. Microphone 8a-
8c is arranged at a position where the sound pressure near the occupant's ear position can be measured, and the residual noise in the passenger compartment 3 measured is
The residual noise signal ep ₁ is supplied to the controller 10. Although three microphones are shown in FIG. 1, the microphones are actually arranged at a large number of positions such as in the vicinity of the occupant's ear position. Here, the number of microphones is L, the residual noise signal ep _l subscript l (l =
, 1, ..., L) represent which of the microphones the residual noise signal is output from.

The controller 10 executes a predetermined calculation process based on the crank angle signal X and the residual noise signal ep _l, and a control sound for canceling the muffled sound transmitted into the vehicle interior 3 is output to the loudspeaker 9a ,. A drive signal yp _m is supplied to each of the loudspeakers 9a and 9b so as to be emitted from 9b. In addition, the loudspeaker,
Although two are shown in FIG. 1, in reality, a larger number of loudspeakers are arranged at respective positions in the vehicle interior 3. Here, assuming that the number of loudspeakers is M, the subscript m (m = 1, 2, ..., M) of the drive signal yp _m is which of the loudspeakers the drive signal is supplied to. Is represented.

The controller 10 comprises a microcomputer, necessary interface circuits, etc., and its specific functional configuration is shown in FIG. That is, the controller 10 is functionally
A reference signal generation unit 11 as reference signal generation means for generating a reference signal x, which is a periodic signal corresponding to a predetermined order component of a muffled sound generated in the engine 4 based on the crank angle signal X, a loudspeaker 9a, The same number of adaptive digital filters W _m as the number M of 9b, the reference signal x, and the filter coefficient W _{mi of} each adaptive digital filter W _m (i =
0, 1, ..., I-1: I is an adaptive digital filter W _m
(The number of taps) and a drive signal generation unit 12 as a drive signal generation unit that calculates a drive signal yp _m, and an engine rotation speed calculation unit 13 that calculates an engine rotation speed N based on the crank angle signal X. , The loudspeakers 9a and 9b and the microphones 8a to 8 in the passenger compartment 3.
Transfer function filter C ^ which is a digital filter in which the transfer function between c is modeled in the form of a finite impulse response function.
_lm and a filter coefficient updating unit 14 that updates each filter coefficient W _mi of the adaptive digital filter W _m so that the drive signal yp _m becomes a signal capable of reducing noise in the vehicle interior 3.

The filter coefficient updating unit 14 includes a reference signal x
And the filter coefficient C ^ of each transfer function filter C ^ _lm
lmj (j = 0, 1, ..., J-1: J is the number of taps of the transfer function filter C ^ _lm ) and a reference processed signal r _lm obtained by convolution with the residual noise signal ep _l are supplied. Thus, the filter coefficient updating unit 14 updates each filter coefficient W _mi of the adaptive digital filter W _m based on the reference processed signal r _lm and the residual noise signal ep ₁ and according to the LMS algorithm. Therefore, the update formula of the filter coefficient W _mi is as shown in the following formula (1), where the convergence coefficient is α.

[0024] On the other hand, the reference signal generation unit 13 generates a sine wave x ₂ having the same period as the second component of the crank angle signal X, as shown in FIG. a generating unit 11a, a fourth-order component corresponding sine wave generator 11b to generate the same period sine wave x ₄ with fourth-order component of the crank angle signal X, and the amplification portion 11c of the variable gain sine wave x ₂ are input , A variable gain amplifier 11d to which the sine wave x ₄ is input, and an amplifier 11d based on the engine speed N
A gain control unit 11e that adjusts the gains G ₂ and G ₄ of c and 11d, and an addition unit 11f that adds the outputs of the amplification units 11c and 11d and outputs as a reference signal x are provided.

Specifically, the sine wave generator 1 for the second order component
1a generates a sine wave x ₂ having a 180 ° interval of the crank angle signal X as one cycle, and generates a sine wave generator 11 for a fourth-order component.
b is configured to generate a sine wave x ₄ having a 90-degree interval of the crank angle signal X as one cycle. In addition, the gain control unit 11e includes the gain G ₂ of the amplification unit 11c and the amplification unit 1
The gain G ₄ of 1d is set based on the engine rotation speed N with reference to a preset map as shown in FIG.

That is, the engine speed N is 3100 rp
In the range of m or more, the gain G ₂ is set to 1 and the gain G ₄ is set to 0, and the engine speed N is 2900.
In the range of rpm or less, the gain G ₂ is set to 0 and the gain G ₄ is set to 1, and the engine speed N is 29.
In the range of 0 to 3100 rpm, the gain G ₂ increases linearly with the increase of the engine speed N, and the gain G _2
4 will decrease linearly as the engine speed N increases. Therefore, “G ₂ + G ₄ = 1” always holds.

FIG. 5 is a flowchart showing the outline of the processing executed in the controller 10. The operation of this embodiment will be described below with reference to FIG. That is, the controller 1
The process at 0 is executed as an interrupt process at every predetermined sampling period. First, at step 101, the crank angle signal X is read,
Next, in step 102, the crank angle signal X
The sine wave x ₂ corresponding to the second-order component of the crankshaft and the sine wave x ₄ corresponding to the fourth-order component of the crankshaft are generated on the basis of the angular position of the crankshaft known from the above. Since the arithmetic processing in the controller 10 is digital signal processing, the sine waves x ₂ and x ₄ are instantaneous values at the sampling time n.

Next, the routine proceeds to step 103, where the present engine speed N is calculated based on the crank angle signal X. It should be noted that the engine rotation speed N is easily obtained by counting the number of pulse signals input within a unit time, for example, if the crank angle signal X is a pulse signal synchronized with the rotation of the crankshaft by 1 or 2 degrees. be able to. Then, the process proceeds to step 104, the gains G ₂ and G ₄ are set by referring to the map as shown in FIG. 4 based on the engine rotation speed N obtained in step 103, then the process proceeds to step 105, and The reference signal x is calculated according to the equation (2).

X = G ₂ x ₂ + G ₄ x ₄ (2) Therefore, since the gains G ₂ and G ₄ are set as described above based on the engine rotation speed N, the reference signal x is
When the engine speed N is 3100 rpm or higher,
Of the order components of the crank angle signal X, the sine wave x _{2 has the} same cycle as the second order component, and the engine speed N is 2900r.
When it is pm or more, it becomes a sine wave x ₄ having the same cycle as the fourth order component of the order component of the crank angle signal X, and when the engine speed N is 2900 to 3000 rpm, these sine waves x ₂ and x _{4 are obtained.} Are superimposed at a ratio according to the respective gains G ₂ and G ₄ .

That is, in this embodiment, N = 2900 to 3
At 100 rpm, the order component of the crank angle signal X corresponding to the reference signal x is switched between the second order and the fourth order. When the reference signal x is calculated, the process proceeds to step 106 and the reference signal x is transferred to the transfer function filter C ^.
_The reference processed signal r _lm is calculated by filtering with _lm , then the process _proceeds to step 107, the residual noise signal ep ₁ is read, and then the process _proceeds to step 108, where the adaptive digital filter according to the above equation (1). Update each filter coefficient W _mi of W _m .

At step 108 all filter coefficients W _mi
Of After completing the update process proceeds to step 109, the reference signal x filtered by an adaptive digital filter W _m by calculating a drive signal yp _m, corresponding loudspeakers 9a the driving signal yp _m in step 110, 9b Output to. Then, control sounds are emitted from the loudspeakers 9a and 9b into the passenger compartment 3. However, immediately after the start of life, each filter coefficient W _mi of the adaptive digital filter W _m does not always converge to the optimum value. The control sound does not necessarily reduce the muffled sound in the passenger compartment 3.

However, when the processing shown in FIG. 5 is repeatedly executed, each filter coefficient W _mi of the adaptive digital filter W _m is updated based on the LMS algorithm so that the noise in the vehicle interior 3 is reduced. , Loudspeaker 9
The noise transmitted from the engine 4 into the vehicle interior 3 is canceled by the control sounds emitted from the a and 9b, and the noise inside the vehicle interior 3 is reduced.

Here, in the vehicle active noise control system 1 using the loudspeaker as in this embodiment, since the frequency characteristic of the loudspeaker drops on the low frequency side,
For example, as shown in FIG. 6, the engine speed is 3000
Below rpm, the noise reduction effect cannot be obtained so much. Note that FIG. 6 shows the noise reduction effect when the drive signal yp _m is generated using the sine wave having the same cycle as the secondary component of the crankshaft rotation as the reference signal, and the engine rotation speed is 3
At 000 rpm, the frequency of the drive signal yp _m is 1
It becomes 00 Hz.

That is, the frequency of the drive signal yp _m is 100
If the frequency is equal to or higher than Hz, a normal control sound according to the drive signal yp _m should be emitted from the loudspeakers 9a and 9b,
The controllable range by the loudspeakers 9a and 9b is shown in FIG.
Will exist above 100 Hz as shown in FIG. Therefore, the loudspeaker 9 is driven by the drive signal yp _m .
In order to operate the a and 9b to obtain the noise reduction effect, the frequency of the reference signal x which is the basis of the drive signal yp _m is 100
It is necessary to be higher than Hz.

Therefore, in the configuration of this embodiment, the point where the engine rotational speed N is 3000 rpm at which the frequency of the secondary component of the crank angle signal X is 100 Hz is approximately the boundary.
Crank angle signal X that serves as a reference when generating the reference signal x
Since the order component is switched, the reference signal x is generated based on the fourth order component of the crank angle X in the range where the engine speed N is 3000 rpm or less, and the frequency of the drive signal yp _m is the loudspeaker 9a, 9b falls within the controllable range, so that a control sound corresponding to the drive signal yp _m is emitted into the vehicle interior 3.

However, the engine speed N is 3000r.
In the range of pm or less, the reference signal x is mainly generated based on the fourth-order component of the crank angle X, so that the muffled sound generated due to the second-order component of the crankshaft rotation cannot be largely canceled. As shown in FIG. 8, which shows the frequency characteristic of the vehicle interior noise of a vehicle equipped with a 4-cylinder reciprocating engine, not only the second-order component but also the noise due to the other-order components exist in the vehicle interior 3. Therefore, even in the range in which the reference signal x based on the fourth-order component is generated,
The noise in the vehicle interior 3 is reduced as a whole.

Further, in this embodiment, the reference signal x
The order component of the crank angle signal X, which is the basis of
As shown in FIG. 4, which shows the relationship between the engine speed N and the gains G ₂ and G ₄ , instead of switching suddenly at rpm, the sine wave x ₂ having the same cycle as the secondary component of the crank angle signal X is obtained. Is overlapped with the range in which the sine wave x ₄ having the same period as the fourth-order component of the crank angle signal X is generated, and the gains G ₂ and G ₄ are set to the engine rotation speed. Speed N is 2900-3000rp
Since it gradually changes in the range of m, the generation of unpleasant noise can be prevented.

More specifically, in a situation where the reference signal x is generated only based on the secondary component of the crank angle signal X, each filter coefficient W _mi of the adaptive digital filter W _m is as shown in FIG. As shown in a) and (b), both the level and the phase are applicable to the second-order component, but not to the other order components at all. Therefore, when the situation is suddenly switched to the situation in which the reference signal x is generated based only on the fourth-order component, the filter coefficient W _mi of the adaptive digital filter W _m cannot follow the sudden change, and the loudspeakers 9a and 9b. May cause an unpleasant sound.

On the other hand, according to the configuration of the present embodiment, the situation in which the reference signal x generated based on both the second-order component and the fourth-order component before the order component is completely switched is used for control. In addition, in the situation where both order components are used for control, the ratio of each order component gradually changes according to the change of the engine rotation speed N. 9 (c) and 9 (d), after the level and phase of each filter coefficient W _mi of the adaptive digital filter W _m have once adapted to both the second-order component and the fourth-order component, the order switching is performed. Will be completed. Therefore, even if the reference signal x is generated based on only one order after that, no unpleasant sound is generated.

Here, in this embodiment, the filter coefficient
Update unit 14, transfer function filter C ^ _lmAnd step 10
Adaptive processing means is constituted by the processing of 6 to 108, and
For the engine rotation speed calculation unit 13 and the process of step 103
Therefore, the frequency detecting means is configured, and the amplifying units 11c, 11
d, gain control section 11e, addition section 11f and step 1
The order switching means is constituted by the processing of 04 and 105.
It

FIG. 10 and FIG. 11 are views showing the configuration of the second embodiment of the present invention. In this embodiment as well, the present invention is applied to a vehicle active noise control system similar to the first embodiment. It is applied. The same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. Figure 1
0 is a block diagram showing the functional configuration of the controller 10, and FIG. 11 is a block diagram showing the functional configuration of the reference signal generating unit 11 in the controller 10. As shown in these, in the present embodiment, the reference signal generating unit 11 is shown. By omitting the addition section of the output stage, both the sine wave x ₂ having the same cycle as the second-order component of the crank angle signal X and the sine wave x ₄ having the same cycle as the fourth-order component of the crank angle signal X are used as references. The controller 10 is configured to output as signals x ₂ and x _4.
Are the adaptive digital filters W _2m and W _4m and the drive signal generator 12 individually for each of the two reference signals x ₂ and x _4.
A and 12B, filter coefficient updating units 14A and 14B, and a transfer function filter C _lm .

Then, the drive signal generators 12A and 12B
Are added by the adder 15 and the output of the adder 15 is supplied to the loudspeaker as the drive signal yp _m . Further, unlike the first embodiment, the gain control unit 11e of the reference signal generation unit 11 determines the order component of the crank angle signal X, which is the basis of the reference signal x, at the boundary of the engine rotation speed N of 3000 rpm. It is designed to be completely switched, specifically, N is 3000 rpm.
Gain G ₂ = 1 and gain G ₄ = 0 when N exceeds 3000 rpm, and gain G ₂ =
0 and the gain G ₄ = 1 are set.

FIG. 12 is a flow chart showing the outline of the processing executed in the controller 10 of this embodiment, which is executed as an interrupt processing at every predetermined sampling period, like the processing in the first embodiment. The same processes as those in the controller 10 in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

That is, in this embodiment, step 10
The process directly proceeds from step 1 to step 103 without passing through step 102, calculates the engine speed N, and then proceeds to step 201. In this step 201, it is judged whether or not the engine rotation speed N exceeds 3000 rpm, and if the judgment is "YES", step 10
After executing the processes of 2A, 106A, 107A, 108A, and 109A, the process proceeds to step 110, and when the determination is “NO”, steps 102B, 106B, 1
After executing the processes of 07B, 108B, and 109B, the process proceeds to step 110.

Here, when the process proceeds to step 102A, the crankshaft 2 is determined based on the angular position of the crankshaft found from the crank angle signal X read in step 101.
Generate a sine wave x ₂ corresponding to the next component, step 106
To filter the A and the sine wave x ₂ with transfer function filter C ^ _lm generates a reference processed signal r _lm, then reads the residual noise signal e _l in step 107A. Then, the process proceeds to step 108A, and each filter coefficient W _2mi of one adaptive digital filter W _2m is updated according to the above equation (1). However, in this case, the sine wave x ₂ is used as the reference signal x.

In step 108A, each filter coefficient W _2mi
When the update of is completed, the process proceeds to step 109A, and the sine wave x ₂ is filtered by one of the adaptive digital filters W _2m to generate the drive signal yp _m . On the other hand, step 1
In the case of the shift to 02B, a sine wave x ₄ corresponding to the fourth-order component of the crankshaft is generated based on the crankshaft angular position found from the crank angle signal X read in step 101, and the sine wave is generated in step 106B. It generates the reference processed signal r _lm to filter x ₄ in transfer function filter C ^ _lm, then reads the residual noise signal e _l in step 107B. Then, the _{process proceeds} to step 108B, where each filter coefficient W _{4mi of the} other adaptive digital filter W _4m.
Is updated according to the above equation (1). However, in this case, the sine wave x ₄ is used as the reference signal x.

In step 108B, each filter coefficient W _4mi
When the updating of the sine wave is completed, the process proceeds to step 109B, and the sine wave x ₄ is filtered by the other adaptive digital filter W _4m to generate the drive signal yp _m . That is, in the present embodiment, the engine rotation speed N is calculated in step 103, it is determined in step 201 whether or not the engine rotation speed N exceeds 3000 rpm, and in accordance with the determination, steps 102A and subsequent steps are performed. Process or step 102B
Since the subsequent processing is executed, the order component of the crank angle signal X corresponding to the reference signal x is switched at the engine rotation speed N of 3000 rpm as a boundary. A control sound capable of reducing noise is emitted from the loudspeaker, and the same effect as that of the above-described first embodiment that the noise is reduced as a whole can be obtained.

Further, in the present embodiment, as a result of providing the determination in step 201, with N = 3000 rpm as a boundary,
The order component of the crank angle signal X, which is the basis of the reference signal x, is completely switched, but there are two systems so as to individually correspond to the number of order components to be switched, that is, each of the second order component and the fourth order component. Adaptive digital filter W
Provided with a _2m and W _4m, when the reference signal sine wave x ₂ performs the driving signal generation processing using the update processing and the adaptive digital filter W _2m for one of the adaptive digital filter W _2m, sine When the wave x ₄ is used as the reference signal, the update process for the other adaptive digital filter W _4m and its adaptive digital filter W _4m
Since the drive signal generation process using is performed, even if the order component suddenly switches, the adaptive digital filter used after the switching has a filter coefficient adapted to the order component after switching. That is, the filter coefficient of the adaptive digital filter cannot follow the switching, and therefore no unpleasant sound is generated at the time of switching.

In this embodiment, the engine rotation speeds N are changed when switching from secondary to quaternary and switching from quaternary to quadratic.
Change the engine speed when switching next from 4th to 2nd
The hunting phenomenon may be avoided by making the engine rotation speed a little smaller than that at the time of next switching so as to have a hysteresis.

In this embodiment, the filter coefficient updating units 14A and 14B and steps 106A to 108 are used.
An adaptive processing means is constituted by the processing of A, 106B to 108B, and the engine speed calculator 13 and step 1
The frequency detection means is configured by the processing of 03, and the order switching means is configured by the amplification sections 11c and 11c, the gain control section 11e, the addition section 11f, and the processing of step 201.

FIGS. 13 to 15 are views showing a third embodiment of the present invention. In this embodiment, the active vibration control system according to the present invention reduces vibrations transmitted from the engine 4 to the vehicle body. The present invention is applied to an active vibration control device 20 for a vehicle. The same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. That is, an engine mount 21 as a control vibration source is interposed between the engine 4 as a vibration source and the vehicle body, and the engine mount 21 is configured to include, for example, an electromagnetic actuator and is supplied from the controller 30. This is a so-called active engine mount that generates an active control force according to the drive signal yv. Further, an acceleration sensor 22 as a residual vibration detecting means is fixed on the vehicle body side of the vehicle 2 in the vicinity of the position where the engine mount 21 is provided. The acceleration sensor 22 is connected to the vehicle body from the engine 4 via the engine mount 21. The residual vibration transmitted to the side is detected, and this is supplied to the controller 30 as a residual vibration signal ev. Also, the controller 3
The crank angle signal X output from the crank angle sensor 5 is also supplied to 0. The controller 30 is the first
It has substantially the same function as the controller 10 in the embodiment, and specifically, as shown in FIG. 14, a reference signal generation unit 31, a drive signal generation unit 32, an engine rotation speed calculation unit 33, a filter coefficient update. The unit 34 and the transfer function filter C ^ are provided. The transfer function filter C ^ is a digital filter that models the transfer function between the engine mount 21 and the acceleration sensor 22 in the form of a finite impulse response function.

Further, the reference signal generator 31 has substantially the same function as the reference signal generator 11 in the first embodiment, and specifically, as shown in FIG. Generate a sine wave x ₁ with the same period as the first-order component of
And the next component corresponding sine wave generating unit 31a, a second order component corresponding sine wave generator 31b for generating a sine wave x ₂ having the same period as the second-order component of the crank angle signal X, the variable gain sine wave x ₁ is input Amplifier 31c, a gain variable amplifier 31d to which the sine wave x ₂ is input, a gain controller 31e that adjusts the gains G ₁ and G ₂ of the amplifiers 31c and 31d based on the engine speed N, An adder 31f that adds the outputs of the amplifiers 31c and 31d and outputs as the reference signal x
And are equipped with.

Specifically, the sine wave generator 3 corresponding to the first-order component
1a generates a sine wave x ₁ having a 360-degree interval of the crank angle signal X as one cycle, and generates a sine wave generator 31 for the secondary component.
b is configured to generate a sine wave x ₂ with a 180-degree interval of the crank angle signal X as one cycle. The gain control unit 31e has a gain G ₂ of gain G ₁ and the amplification portion 31d of the amplifying section 31c, based on the engine rotational speed N,
The map is set with reference to a preset map as shown in FIG.

That is, the engine speed N is 3300 rp
In the range of m or more, the gain G ₁ is set to 1 and the gain G ₂ is set to 0, and the engine speed N is 3100.
In the range below rpm, the gain G ₁ is set to 0 and the gain G ₂ is set to 1, and the engine speed N is 31.
In the range of 0 to 3300 rpm, the gain G ₁ increases linearly as the engine speed N increases, and the gain G 1
₂ will decrease linearly as the engine speed N increases. Therefore, “G ₁ + G ₂ = 1” always holds.

The contents of processing in the controller 30 are substantially the same as those in FIG. 5 described in the first embodiment, and therefore, the drive signal in the situation where the filter coefficient W _i of the adaptive digital filter W is appropriately converged. If the control vibration according to yv is generated in the engine mount 21, the vibration transmitted from the engine 4 to the vehicle body side is reduced, and the noise level in the vehicle interior 3 is reduced.

Here, in the vehicle active vibration control system 20 using the engine mount 21 having the electromagnetic actuator built therein as in this embodiment, the frequency characteristic of the electromagnetic actuator drops on the high frequency side. Figure 6
As shown in (1), when the engine speed is 3200 rpm or more, the vibration reducing effect cannot be obtained so much. That is, FIG.
As shown in FIG. 7, the controllable range by the engine mount 21 is below about 106 Hz.

However, with the configuration of this embodiment, the order component of the crank angle signal X, which is the reference when the reference signal x is generated, is switched with the point where the engine speed N is 3200 rpm as a boundary. Therefore, when the engine speed N is 3300 rpm or more, the crank angle X
Since the reference signal x is generated based on the first-order component of the drive signal yp _m , the frequency of the drive signal yp _m falls within the controllable range of the electromagnetic actuator in the engine mount 21, and the vibration reducing effect is obtained over a wide range. is there.

Also in this embodiment, instead of suddenly switching the order component of the crank angle signal X, which is the basis of the reference signal x, as in the first embodiment, the first order of the crank angle signal X is changed. The range in which the sine wave x ₁ having the same cycle as the component and the range in which the sine wave x ₂ having the same cycle as the secondary component of the crank angle signal X are generated overlap each other, and Since the gains G ₁ and G ₂ are designed to gradually change within the engine speed N range of 3100 to 3300 rpm, the occurrence of unpleasant vibration can be prevented.

It is also possible to prevent the occurrence of unpleasant vibration by making the inside of the controller 30 similar to that of the second embodiment. Here, in the present embodiment, the filter coefficient updating unit 34 and the transfer function filter C ^ constitute an adaptive processing unit, the engine rotation speed computing unit 33 constitutes a frequency detecting unit, and the amplifying units 31c, 31d ,. Gain control unit 31e and addition unit 11
The order switching means is constituted by f.

FIG. 18 is a diagram showing a fourth embodiment of the present invention, and this embodiment has the structure of both the first embodiment (or second embodiment) and the third embodiment. Is characterized by. The same components as those in the above-described embodiments are designated by the same reference numerals, and the duplicated description will be omitted. That is, as described in each of the above embodiments, the loudspeakers 9a and 9b are not good at controlling on the low frequency side. Therefore, the control based on the secondary component of the crank angle signal X causing the muffled sound is on the high frequency side. However, since the engine mount 21 is not good at controlling on the high frequency side, control based on the secondary component of the crank angle signal X that causes muffled noise is possible only on the low frequency side. .

Therefore, when only one of the vehicle active noise control device 1 and the vehicle active vibration control device 20 is provided, control based on the secondary component of the crank angle signal X is not performed. Bands will exist.
However, with the configuration of the present embodiment, the vehicle active noise control device 1 and the vehicle active vibration control device 20 are in a relationship of complementing each other's weak points, so that the crank is used in almost all bands. The control based on the secondary component of the angle signal X is performed, so that the muffled sound in the vehicle interior 3 can be reduced.

Other functions and effects are the same as those in the above-mentioned respective embodiments. In each of the above embodiments, specific numerical values of the engine rotation speed N are shown as the timings for switching the orders, but these numerical values are merely examples and may be appropriately selected according to various specifications of the vehicle to which they are applied. Is. The order component to be switched is not limited to the order between the second order and the fourth order or between the first order and the second order shown in each of the above-described embodiments, and other order components may be targeted. For example, in the case of a vehicle equipped with a 6-cylinder engine, it is possible to switch between the third order and the sixth order for noise reduction control, and to switch between the third order and the sixth order for vibration reduction control.

Furthermore, in each of the above embodiments, the engine 4 is taken as an example of the noise source and the vibration source, but the noise source and the vibration source to which the present invention can be applied are not limited to the engine 4, and the cycle is not limited. A noise source or a vibration source other than the engine 4 may be used as long as the noise or vibration is generated. Also,
The application itself of the present invention is not limited to the vehicle 2 and may be, for example, a device that reduces noise and the like emitted from a duct or the like.

[0064]

As described above, according to the present invention,
Since the order component of the periodic vibration or noise corresponding to the reference signal is switched according to the frequency of the vibration or noise, the frequency of the drive signal is kept within the frequency band in which the control sound source or the control vibration source operates normally. It is possible to obtain a noise reduction effect or a vibration reduction effect over a wide range.

In particular, according to the invention described in claim 2, 3, 5 or 6, there is an effect that it is possible to prevent an unpleasant sound or an unpleasant vibration from occurring at the time of order switching.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of a controller in the first embodiment.

FIG. 3 is a block diagram showing a functional configuration of a reference signal generation unit in the first embodiment.

FIG. 4 is a graph showing a relationship between engine speed N and gains G ₂ and G ₄ in the first embodiment.

FIG. 5 is a flowchart showing an outline of processing executed in the controller in the first embodiment.

FIG. 6 is a characteristic diagram illustrating a general noise reduction effect and vibration reduction effect.

FIG. 7 is a graph illustrating a controllable range by a loudspeaker.

FIG. 8 is a frequency characteristic diagram of vehicle interior noise.

FIG. 9 is a diagram illustrating an adaptive situation of an adaptive digital filter.

FIG. 10 is a block diagram showing a functional configuration of a controller in the second embodiment.

FIG. 11 is a block diagram showing a functional configuration of a reference signal generation unit in the second embodiment.

FIG. 12 is a flowchart showing an outline of processing executed in a controller in the second embodiment.

FIG. 13 is a conceptual diagram showing an overall configuration of a third embodiment.

FIG. 14 is a block diagram showing a functional configuration of a controller in the third embodiment.

FIG. 15 is a block diagram showing a functional configuration of a reference signal generation unit in the third embodiment.

FIG. 16 is a graph showing the relationship between engine speed N and gains G ₂ and G ₄ in the third embodiment.

FIG. 17 is a graph illustrating a controllable range by the engine mount.

FIG. 18 is a conceptual diagram showing the overall structure of a fourth embodiment.

[Explanation of symbols]

1 Active noise control device for vehicle 2 Vehicle 3 Vehicle compartment (space) 4 Engine (noise source, vibration source) 5 Crank angle sensor 8a, 8b, 8c Microphone (residual noise detection means) 9a, 9b Loudspeaker (control sound source) 10, 30 Controller 11, 31 Reference signal generator (reference signal generator) 11a Second-order component corresponding sine wave generator 11b Fourth-order component corresponding sine wave generator 11c, 11d, 31c, 31d Amplifier 11e, 31e Gain controller 11f, 31f adder 12, 12A, 12B, 32 drive signal generator (drive signal generator) 13, 33 engine speed calculator (frequency detector) 14, 14A, 14B filter coefficient updater 20 active vibration for vehicle Control device 21 Engine mount (controlled vibration source) 22 Acceleration sensor (residual vibration detection means)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koji Yamada 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd.

Claims (6)

[Claims] 1. A control sound source capable of generating a control sound in a space where periodic noise is transmitted from a noise source, and a period corresponding to a predetermined order component of the periodic noise based on a noise generation state of the noise source. Signal generating means for generating a reference signal composed of a specific signal, residual noise detecting means for detecting residual noise at a predetermined position in the space and outputting the residual noise signal, an adaptive digital filter having a variable filter coefficient, and Drive signal generating means for generating a signal for driving the control sound source by filtering the reference signal with the adaptive digital filter; and the noise reducing means for reducing noise in the space based on the reference signal and the residual noise signal. An active noise control device comprising: adaptive processing means for updating a filter coefficient of an adaptive digital filter, wherein a frequency for detecting a frequency of the noise is detected. A detection means and an order switching means for switching the order of a predetermined order component of the periodic noise corresponding to the reference signal in accordance with the frequency of the noise detected by the frequency detection means. Active noise control device. 2. The active noise according to claim 1, wherein the order switching means overlaps a frequency band for generating a reference signal corresponding to one order with a frequency band for generating a reference signal corresponding to another order. Control device. 3. The active noise control system according to claim 1, further comprising an adaptive digital filter for each reference signal corresponding to each order component switched by the order switching means. 4. A control vibration source capable of generating a control vibration that interferes with a periodic vibration emitted from a vibration source, and a predetermined order component of the periodic vibration based on a vibration generation state of the vibration source. Reference signal generating means for generating a reference signal formed of a periodic signal, residual vibration detecting means for detecting the vibration after interference and outputting it as a residual vibration signal, an adaptive digital filter with a variable filter coefficient, and the reference signal Drive signal generating means for generating a signal for driving the controlled vibration source by filtering with the adaptive digital filter, and the adaptive digital so as to reduce the vibration after the interference based on the reference signal and the residual vibration signal. In an active vibration control device including adaptive processing means for updating a filter coefficient of a filter, frequency detection means for detecting a frequency of the vibration, An active vibration control, characterized in that: an order switching means for switching the order of a predetermined order component of the periodic vibration corresponding to the reference signal in accordance with the frequency of the vibration detected by the frequency detecting means. apparatus. 5. The active vibration according to claim 4, wherein the order switching means overlaps a frequency band for generating a reference signal corresponding to one order with a frequency band for generating a reference signal corresponding to another order. Control device. 6. The active noise control apparatus according to claim 4, wherein an adaptive digital filter is individually provided for each reference signal corresponding to each order component switched by the order switching means.